The present invention relates to hand dishwashing compositions containing particular types of alkylarylsulfonate surfactants. More particularly, these alkylarylsulfonates have chemical compositions which differ both from the highly branched nonbiodegradable or xe2x80x9chardxe2x80x9d alkylbenzenesulfonates still commercially available in certain countries; and which differ also from the so-called linear alkylbenzenesulfonates which have replaced them in most geographies, including the most recently introduced so-called xe2x80x9chigh 2-phenylxe2x80x9d types.
Typical commercial hand dishwashing compositions incorporate divalent ions (Mg, Ca) to ensure adequate grease performance in soft water. However, the presence of divalent ions in formulas containing anionic, nonionic, or additional surfactants (e.g., amine oxide, alkyl ethoxylate, LAS, alkanoyl glucose amide, alkyl betaines) leads to slower rates of product mixing with water (and hence poor flash foam), poor rinsing, and poor low temperature stability properties. Moreover, preparation of stable dishwashing detergents containing Ca/Mg is very difficult due to the precipitation issues associated with Ca and Mg as pH increases. Consequently, there remains the need for a detergent composition suitable for hand dishwashing, which is stable at low temperatures, and additionally can provide grease removal and tough food cleaning benefits, in hard water and at pH""s, typically pH 9 or lower, where a conventional Ca/Mg system would be unstable and not provide grease removal and tough food cleaning benefits.
U.S. Pat. Nos. 5,026,933; 4,990,718; 4,301,316; 4,301,317; 4,855,527; 4,870,038; 2,477,382; EP 466,558, Jan. 15, 1992; EP 469,940, Feb. 5, 1992; FR 2,697,246, Apr. 29, 1994; SU 793,972, Jan. 7, 1981; U.S. Pat. Nos. 2,564,072; 3,196,174; 3,238,249; 3,355,484; 3,442,964; 3,492,364; 4,959,491; WO 88/07030, Sep. 25, 1990; U.S. Pat. Nos. 4,962,256, 5,196,624; 5,196,625; EP 364,012 B, Feb. 15, 1990; U.S. Pat. Nos. 3,312,745; 3,341,614; 3,442,965; 3,674,885; 4,447,664; 4,533,651; 4,587,374; 4,996,386; 5,210,060; 5,510,306; WO 95/17961, Jul. 6, 1995; WO 95/18084; U.S. Pat. Nos. 5,510,306; 5,087,788; 4,301,316; 4,301,317; 4,855,527; 4,870,038; 5,026,933; 5,625,105 and 4,973,788 are useful by way of background to the invention. The manufacture of alkylbenzenesulfonate surfactants has recently been reviewed. See Vol 56 in xe2x80x9cSurfactant Sciencexe2x80x9d series, Marcel Dekker, New York, 1996, including in particular Chapter 2 entitled xe2x80x9cAlkylarylsulfonates: History, Manufacture, Analysis and Environmental Propertiesxe2x80x9d, pages 39-108 which includes 297 literature references. Documents referenced herein are incorporated in their entirety.
The present invention has numerous advantages beyond one or more of the aspects identified hereinabove, including but not limited to: superior cold-water solubility, for example for cold water cleaning; superior hardness tolerance; and excellent detergency. Further, the invention is expected to provide improved removal of lipid or greasy soils. The development offers substantial expected improvements in ease of manufacture of relatively high 2-phenyl sulfonate compositions, improvements also in the ease of making and quality of the resulting formulations; and attractive economic advantages.
The present invention is based on an unexpected discovery that there exist, in the middle ground between the old, highly branched, less biodegradable alkylbenzenesulfonates and the new linear types, certain alkylbenzenesulfonates which are both more highly performing than the latter and more biodegradable than the former.
The new alkylbenzenesulfonates are readily accessible by several of the hundreds of known alkylbenzenesulfonate manufacturing processes. For example, the use of certain dealuminized mordenites permits their convenient manufacture.
In accordance with the present invention, a novel hand dishwashing composition is provided. This novel hand dishwashing composition comprises
i) from about 0.01% to about 99.99% by weight of composition of a surfactant mixture, said surfactant mixture comprising:
an alkylarylsulfonate surfactant system comprising at least two alkylarylsulfonate surfactants of the formula: 
wherein:
L is an acyclic aliphatic hydrocarbyl of from 6 to 18 carbon atoms in total;
M is a cation or cation mixture and q is the valence thereof;
a and b are numbers selected such that said alkylarylsulfonate surfactant is electroneutral;
Rxe2x80x2 is selected from H and C1 to C3 alkyl;
Rxe2x80x3 is selected from H and C1 to C3 alkyl;
Rxe2x80x2xe2x80x3 is selected from H and C1 to C3 alkyl;
both of Rxe2x80x2 and Rxe2x80x3 are nonterminally attached to L and at least one of Rxe2x80x2 and Rxe2x80x3 is C1 to C3 alkyl; and
A is aryl;
wherein:
said alkylarylsulfonate surfactant system comprises two or more isomers with respect to positions of attachment of Rxe2x80x2, Rxe2x80x3 and A to L;
in at least about 60% of said alkylarylsulfonate surfactant system, A is attached to L in the position which is selected from positions alpha- and beta- to either of the two terminal carbon atoms of L; and
wherein further said alkylarylsulfonate surfactant system has at least one of the following properties:
said alkylarylsulfonate surfactant system has a ratio of nonquaternary to quaternary carbon atoms in L of at least about 5:1 by weight, when said quaternary carbon atoms are present; or
percentage biodegradation, as measured by the modified SCAS test, that exceeds tetra propylene benzene sulphonate;
ii) from about 0.0001% to about 99.99% by weight of composition of a conventional hand dishwashing adjunct; and
iii) from about 0.01% to about 7% by weight of composition of a divalent ion selected from the group consisting of magnesium, calcium and mixtures thereof.
More preferably, percentage biodegradation in absolute terms, is preferably at least about 60%, more preferably at least 70%, still more preferably at least 80% and most preferably at least 90%, as measured by the modified SCAS test (described herein after).
In the hand dishwashing composition, the surfactant system will preferably comprise at least two, preferably at least four, more preferably at least eight, even more preferably at least twelve, even more preferably still at least sixteen and most preferably at least twenty, isomers and/or homologs of alkylarylsulfonate surfactant of formula (I). xe2x80x9cIsomersxe2x80x9d, which are described herein after in more detail, include especially those compounds having different positions of attachment of the moieties Rxe2x80x2 and/or Rxe2x80x3 to the L moiety. xe2x80x9cHomologsxe2x80x9d vary in the number of carbon atoms contained in the sum of L, Rxe2x80x2 and Rxe2x80x3.
The hand dishwashing composition will preferably contain at least about 0.1%, more preferably at least about 0.5%, even more preferably still, at least about 1% by weight of said composition of the surfactant mixture. The hand dishwashing composition will also preferably contain no more than about 80%, more preferably no more than about 60%, even more preferably, no more than about 40% by weight of said composition of the surfactant mixture.
All percentages, ratios and proportions herein are by weight, unless otherwise specified. All temperatures are in degrees Celsius (xc2x0 C.) unless otherwise specified. All documents cited are in relevant part, incorporated herein by reference.
The present invention relates to novel hand dishwashing compositions. The surfactant system comprises at least two alkylarylsulfonate surfactants of the formula: 
wherein M is a cation or cation mixture. Preferably, M is an alkali metal, an alkaline earth metal, ammonium, substituted ammonium or mixtures thereof, more preferably sodium, potassium, magnesium, calcium or mixtures thereof. The valence of said cation, q, is preferably 1 or 2. The numbers a and b are selected such that said mixture is electroneutral; a and b are preferably 1 or 2, and 1, respectively.
A is selected from aryl. Preferably, Ar is benzene, toluene, xylene, naphthalene, and mixtures thereof, more preferably Ar is benzene or toluene, most preferably benzene.
Rxe2x80x2 is selected from H and C1 to C3 alkyl. Preferably, Rxe2x80x2 is H or C1 to C2 alkyl, more preferably, Rxe2x80x2 is methyl or ethyl, most preferably Rxe2x80x2 is methyl. Rxe2x80x3 is selected from H and C1 to C3 alkyl. Preferably, Rxe2x80x3 is H or C1 to C2 alkyl, more preferably, Rxe2x80x3 is H or methyl. Rxe2x80x3 is selected from H and C1 to C3 alkyl. Preferably Rxe2x80x2xe2x80x3 is H or C1 to C2 alkyl, more preferably, Rxe2x80x2xe2x80x3 is H or methyl, most preferably Rxe2x80x2xe2x80x3 is H. Both of Rxe2x80x2 and Rxe2x80x3 are nonterminally attached to L. That is, Rxe2x80x2, and Rxe2x80x3 do not add to the overall chain length of L, but rather, are groups branching from L. Also, at least one of Rxe2x80x2 and Rxe2x80x3 is C1 to C3 alkyl. This limits L to a hydrocarbyl molecule with at least one alkyl branch.
L is an acyclic aliphatic hydrocarbyl of from 6 to 18, preferably from 9 to 14 (when only one methyl branching), carbon atoms in total. The preferred L is a moiety Rxe2x80x3xe2x80x3xe2x80x94C(xe2x80x94)H(CH2)vC(xe2x80x94)H(CH2)xC(xe2x80x94)H(CH2)yxe2x80x94CH3, which includes the Rxe2x80x3xe2x80x3, but not Rxe2x80x2, Rxe2x80x3 or the A moiety, in the formula (II) below 
wherein Rxe2x80x2, Rxe2x80x3, Rxe2x80x2xe2x80x3, A, M, q, a and b are hereinbefore defined. Rxe2x80x3xe2x80x3 is selected from H, or C1 to C4 alkyl.
Preferably Rxe2x80x3xe2x80x3 is H or C1 to C3 alkyl, more preferably Rxe2x80x3xe2x80x3 is H or C1 to C3 alkyl, most preferred, Rxe2x80x3xe2x80x3 is methyl or ethyl. The numbers of the methylene subunits, v, x and y are each independently integers from 0 to 10 provided that the total number of carbons attached to A is less than about 20. This number is inclusive of Rxe2x80x2, Rxe2x80x3, Rxe2x80x2xe2x80x3 and Rxe2x80x3xe2x80x3. Furthermore, when Rxe2x80x3xe2x80x3 is C1 the sum of v+x+y is at least 1; and when Rxe2x80x3xe2x80x3 is H the sum of v+x+y is at least 2. In the moiety Rxe2x80x3xe2x80x3xe2x80x94C(xe2x80x94)H(CH2)vC(xe2x80x94)H(CH2)xC(xe2x80x94)H(CH2)yxe2x80x94CH3 the three C(xe2x80x94) indicate the three carbon atoms where A, Rxe2x80x2 and Rxe2x80x3 are attached to the moiety.
The alkylarylsulfonate surfactant system comprises two or more isomers with respect to positions of attachment of Rxe2x80x2, Rxe2x80x3 and A to L. In at least about 60%, preferably, 70%, more preferably, 80%, of the surfactant system, A is attached to L in the position which is selected from positions alpha- and beta- to either of the two terminal carbon atoms of L, preferably A is attached to L in position alpha to a terminal carbon atom of L. When L has its preferred structure, see formula (II) above, at least 40% of Rxe2x80x3xe2x80x3 will be either methyl or ethyl, so that A is alpha- or beta to the terminal carbon. The terms alpha- and beta- mean the carbon atoms which are one and two carbon atoms away, respectively, from the terminal carbon atoms. To better explain this, the structure below shows the two possible alpha- positions and the two possible beta- positions in a general linear hydrocarbon. 
Furthermore, the alkylarylsulfonate surfactant system may have a ratio of nonquaternary to quaternary carbon atoms in L of at least about 5:1 by weight when said quaternary carbon atoms are present. Preferably the weight ratio of nonquaternary to quaternary carbon atoms in L is at least 10:1, more preferably at least 20:1, and most preferably at least 100:1. When L has its preferred structure, see formula (II) above, Rxe2x80x3xe2x80x3 can contain quaternary carbon atoms. That is, tertiary butane.
The alkylarylsulfonate surfactant system may have a percentage biodegradation, as measured by the modified SCAS test as described hereafter, that exceeds tetra propylene benzene sulphonate. Preferred alkylarylsulfonate surfactant systems according to the present invention have a percentage biodegradation of at least about 60%, preferably at least about 70%, more preferably at least about 80%, and most preferably at least about 90%.
Alkylarylsulfonate Surfactant System
The present invention is directed to hand dishwashing compositions comprising a surfactant mixture. This surfactant mixture comprises an alkylarylsulfonate surfactant system containing at least two surfactants of the formula: 
wherein L, M, Rxe2x80x2, Rxe2x80x3, Rxe2x80x2xe2x80x3, q, a, b, A, are as hereinbefore defined. A preferred structure of the sum of L, Rxe2x80x2 and Rxe2x80x3 is: 
wherein Rxe2x80x3xe2x80x3, v, x and y are as hereinbefore defined. A is attached to this structure at the CH next to Rxe2x80x3xe2x80x3. Some possible surfactants present in the alkylaryl sulfonate system include: 
Structures (a) to (h) are only illustrative of some possible alkylarylsulfonate surfactants and are not intended to be limiting in the scope of the invention.
It is also preferred that the alkylarylsulfonate surfactants include at least two xe2x80x9cisomersxe2x80x9d selected from:
i) positional isomers based on positions of attachment of substituents Rxe2x80x2 and to L;
ii) stereoisomers based on chiral carbon atoms in L or its substituents;
iii) ortho-, meta- and para- isomers based on positions of attachment of substituents to Ar, when Ar is a substituted or unsubstituted benzene. This means that L can be ortho-, meta- or para- to A, L can be ortho-, meta- and para- to a substituent on A other than L (for example Rxe2x80x2xe2x80x3), or any other possible alternative.
An example of two type (i) isomers are structures are (a) and (c). The difference is that the methyl in (a) is attached at the 5- position, but in (c) the methyl is attached at the 7- position.
An example of two type (iii) isomers are structures are (1) and (m). The difference is that the sulfonate group in (1) is meta- to the hydrocarbyl moiety, but in (m) the sulfonate is ortho- to the hydrocarbyl moiety.
An example of two type (ii) isomers are structures are (c) and (d). The difference is that these isomers are stereoisomers, the chiral carbon being the 7th carbon atom in the hydrocarbyl moiety.